This proposed research is designed to characterize the permeability and fine structure of regenerating capillaries in skeletal muscle wounds. The objectives for this period of research will be to enhance knowledge about: the permeability of wound regenerating capillaries; regenerating capillary basal lamina; the propagation of endothelium in regenerating capillaries; the morphological structure of regenerating capillaries and their basal lamina; and, glycosaminoglycan localization in healing wounds. The permeability data will be obtained by using an in vivo wound system in the cremaster muscle of guinea pigs and assaying transcapillary exchange with intravascular radioisotope tracers. Unwounded skeletal muscle capillaries will serve as control. The permeability status of the various post wounding stages of the regenerating capillaries will be examined. This transcapillary permeation data will be computed as a permeability ratio (wound/normal) against time for each post wounding period. Composite permeability data for an entire healing period will be expressed as a least squares line equation. In addition the effect of inflammatory mediators and enzymes will be employed in the methodology. The regenerating capillaries will be further characterized by electron microscopy, autoradiography, and histochemistry with particular emphasis on the structure and function of the endothelial sprouts. Qualitative localization and grouping of various glycosaminoglycans in the wound and surrounding connective tissue will be accomplished by light microscopic histochemistry using a linear back wound experimental system in the guinea pig. The altered physiological state of vitamin C deficiency will also be employed in these latter studies. Knowledge of wound healing is of unique importance to clinicians and this investigation, hopefully, will contribute to our further understanding of this biological process.